The Cell Processing Core will provide critical resources that will circumvent many of the technical problems that limit progress in the isolation, molecular characterization, functional analysis and genetic modification of stem cells. Primary among these limitations is an inability to obtain sufficient quantities for purified stem cells needed for experimentation and optimization of the ex-vivo conditions required for efficient transduction. This Core will address that limitation by providing three specific functions. (1) The Core will provide SCOR investigators with access to large quantities of purified stem cells for in vitro studies for large animal model testing, and for clinical trial usage. Taking advantage of the instrumentation and expertise available from within the FHCRC Cryobiology Laboratory, the Core will provide clinical-grade stem cell enrichment for components obtained from both human and large animals such as dogs and primates. (2) The Core will characterize enriched and transduced stem cell populations by performing 2 and 3 color flow cytometric determinations and quantitative CFC and LTC-IC assay. These diagnostic services will provide SCOR investigators with the ability to quality control results from the component processing described above, and to determine efficiencies of gene transduction in the various stem/progenitor cell compartments. (3) The Core will operate a donor recruitment program and a Repository of Cryopreserved Specimens. Established protocols permit collection by apheresis of large quantities of cells from G-CSF-treated or untreated donors, which will provide clinical quantities of cells for the SCOR projects involving human cells. Similarly, the Core will collect and distribute small quantities of human bone marrow. The Repository contains stored marrow of PBSC components from normal donors or decreased patients where permission to use these products for research has been obtained. This Repository will serve as source material for SCOR investigators to obtain specific cells for their research studies. This ability to process and isolate large numbers of cells will greatly enhance and facilitate research studies in the areas of stem cell biology, and to develop and test improvements to gene therapy approaches for the treatment of hematopoietic disorders.